The present invention relates to machines for making and dispensing ice cream shakes, ice cream slushes or the like frozen confections. The term ice cream shake is used to mean a flavored frozen confection which is made from a neutral frozen confection such as ice cream, frozen custard or the like blended and thoroughly mixed with a syrup essence of the desired flavor.
Machines of the type referred to above are known for example from U.S. Pat. Nos. 4,580,905; 3,830 407; 2,669,945; 3,149,756; IT-A-1 103 775. The machines comprise a machine for making the ice cream, means for feeding the ice cream produced to a dispensing door, means for feeding one or more syrup essences and means for mixing the ice cream with the syrup essence. Thus, for example, Italian Patent No. 1,103,775, or U.S. Pat. No. 4,580,905 describe one such machine which comprises a metering/dispensing tube joined to the freezing compartment door and connected to the latter by means of a pipe; a piston which is slidable in the tube and is actuated mechanically, electrically or pneumatically; two or more syrup injectors for flavoring the ice cream; and a rotor for mixing the syrup essence, driven by a drive shaft which is coaxial and concentric with the piston. In machines of the type described above, there is a recurrent problem whereby, when changing the syrup essence used to flavor the plain ice cream dispensed, it is also necessary to clean out any residues of the syrup used previously from the unit.